This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Cell membrane dynamic responses can be influenced by the onset and progression of human diseases. Fluctuations in the phospholipid bilayer and attached spectrin cytoskeleton are known to be altered by cytoskeletal defects, stress, and actin-spectrin dissociations arising from metabolic activity. Proteins transported from invading organisms, such as the malaria-inducing parasite P. falciparum, to specific binding sites in the spectrin cytoskeletal network induce significant alterations to RBC membrane dynamics and nanomechanical response. Using Diffraction Phase Microscopy, we investigate membrane fluctuations in human RBCs parasitized by P. falciparum over the full range of intra-erythrocyte stages.